Real‑Time NIR Testing Cuts Quality‑Control Costs by Up to 90%

Real‑time near‑infrared (NIR) measurement has moved beyond the realm of large resin manufacturers to small compounders, processors and recyclers. Modern NIR devices are lighter, cheaper and simpler to use than ever before.

John Bogart, Managing Director of Kett US in Villa Park, Calif., says the company currently supplies almost 200 instruments for moisture and composition analysis—including a range of NIR systems that serve compounders, recyclers, molders, film and sheet extruders and thermoformers.

For example, the portable NIR moisture analyzer Kett KJT130 sells for roughly $16,000.

Traditional polymer testing—whether a quick moisture check or a full chemical profile—requires sample preparation, reagents, and hours of lab work. Moisture analysis can take 5–15 minutes, while more detailed chemical tests may require 24–48 hours.

“Switching from conventional methods to NIR spectroscopy cuts testing costs by up to 90%,” Bogart explains. “The savings come from eliminating consumables, reducing labor, and cutting the need for repeat tests caused by human error.”

In a simple cost‑comparison, a $20 per‑hour labor rate equates to about $28 for a one‑hour budget. If a moisture‑only test consumes 30 minutes of staff time, the cost is $28. An NIR test, however, takes just 6 seconds (or can run continuously online). That 0.16 % time commitment translates to a 98.84 % reduction in labor cost. A desktop NIR unit therefore costs only about $12 per business day in labor, versus $28 for a traditional test.

Even when factoring in the purchase price of a new instrument, customers see daily savings that reduce testing expenses by at least 90%, according to Bogart. “That’s why even small companies should consider moving to this technology.”

Real‑time NIR measurement offers continuous monitoring and instant quality assurance, enabling 100 % product inspection. The data arrives fast enough for operators to correct a drift in the process immediately, improving batch consistency, yield, and reducing material waste.

How It Works

NIR spectroscopy shines light in the 700–2,500 nanometer range onto a solid, slurry or liquid sample and measures how much light is absorbed at each wavelength. The resulting “optical fingerprint” reveals the sample’s chemical composition once the instrument is calibrated against a laboratory or production standard.

The technology is versatile: handheld, desktop, online or inline units can be installed inside mixers, extruders, pneumatic or vacuum lines, or even pipe‑flow systems using fiber‑optic probes.

Not every application requires the most sophisticated and expensive NIR system. “Don’t buy a Lamborghini for a Ford,” Bogart says. “Choose a moisture meter for simple checks, a composition analyzer for added detail, or a full‑spectrum machine only when you need the extra breadth of analysis.”

For many polymer producers, a moisture meter is all that’s needed. A composition analyzer adds the ability to detect residual oils, solvents or other additives, and a full‑spectrum system provides the most comprehensive data.

The Right Device for the Job

Filter‑based NIR devices—such as moisture meters and composition analyzers—block visible light and allow only selected infrared wavelengths. They’re simpler, cheaper, easier to calibrate and more robust, but they can’t measure as many parameters as full‑spectrum units.

Traditional loss‑on‑drying tests are gravimetric, require sample preparation, take 15 minutes to several hours, and destroy the sample. In contrast, NIR moisture meters provide instant, non‑destructive, and often non‑contact measurements, making them ideal for inspecting raw materials or any point in the production line where precise moisture control is critical.

Desktop NIR moisture analyzers range from $10,000 to $12,000, while portable units cost about $16,000. Online units that fit on a conveyor belt run between $12,000 and $25,000, and inline units—used inside extruders or mixers—cost around $25,000.

Composition analyzers are a step up, measuring multiple components (e.g., moisture, oil, solvent) using about six to seven wavelengths. They replace time‑consuming loss‑on‑drying, Karl Fischer, Soxhlet extraction and gas chromatography methods. Inline composition analyzers typically sell for $28,000–$29,000.

Common applications include verifying recycled plastic feedstock for residual oil or solvent, measuring coating or film thickness, and performing in‑process checks on incoming, intermediate or finished products. Because they can detect multiple organics—water, total oil/fat, protein, sugar, fiber, solvent—composition analyzers are invaluable for troubleshooting failures and returns.

Full‑Spectrum Testing for Complex Analyses

Full‑spectrum NIR devices scan over 500 wavelengths, enabling detection of a wide array of properties once properly calibrated. They can measure moisture, density, viscosity, melt‑flow rate (MFR) and functional group concentrations in real time.

These units are popular in emulsion polymerization (latex, paint, rubber, binder, adhesive) and suspension polymerization (polymer beads). Online composition analyzers such as the Kett BSR1700 sell for $28,000–$29,000 and are suited to conveyor‑belt installations.

Because full‑spectrum devices offer the broadest range of measurable parameters, they command higher prices—typically $40,000 to $60,000—and require more complex calibration, but they’re essential when a single test must capture multiple chemical components or specialized additives.

By integrating the appropriate NIR system into your workflow, you can achieve rapid, accurate analysis, reduce labor and consumable costs, and ultimately improve product quality and profitability.